Ventilated, shaded, waterproof roof structure

ABSTRACT

A domed roof formed by bolting or otherwise fastening together mostly identical prefabricated, preferably hexagonal pans. The pans may have solid tops or may have a central nozzle to accommodate a number of different covers to allow either ventilation, shade, both ventilation and shade, or neither ventilation nor shade, as required. Some variation in the pan shape may be required at the outer edges of the dome to suit the foundation or openings as doors or windows. The invention described herein may be manufactured and used by or for the Government for governmental purposes without the payment to me of any royalty thereon.

I United States Patent 1 Detman 1 Apr. 3, 1973 s41 VENTILATED, SHADED, 2,736,072 2/1956 Woods ..52/81 WATERPROOF ROOF STRUCTURE 2,769,409 11/1956 Rutten ..52/81 2,918,992 12/1959 Gelsavage ..52/81 [76] Inventor: Kenneth D. Detman, 357 Morgan Avenue, Mobile, Ala. 36606 FOREIGN PATENTS OR APPLICATIONS [22] Filed: Feb. 9, 1970 311,105 5/1929 Great Britain ..52/199 [21] Appl' Primary Examiner-Henry C. Sutherland Att0rneyAlva H. Bandy, William G. Gapcynski and [52] 0.8. C1. ..52/22, 52/81, 52/199, Lawrence u th 52/303, 98/43 R 51 Int. Cl. ..E04b 7/08, E04b 1/32 ABSTRACT [58] Field of Search "52,801 303; A domed roof formed by bolting or otherwise fasten- 98/37 43 66; 220/44 R ing together mostly identical prefabricated, preferably hexagonal pans. The pans may have solid tops 01' may [56] References Cited have a central nozzle to accommodate a number of different covers to allow either ventilation, shade, UNITED STATES PATENTS both ventilation and shade, or neither ventilation nor 102,938 5/1870 Heminway et a1. ..220/44R shade, as required. Some variation in the pan shape 1,372,506 3/1921 Hartley ..220/44 R may be required at the outer edges of the dome to suit Mascuch R the foundation or penings as doors or windows 2,181,182 11/1939 Goguen et a1 220/44 R 517 17 11 952 Kimmel 320 44 R The invention described herein may be manufactured 3,072,285 1/ 1963 Aileo 220/44 R and used by or for the Government for governmental 3,210,896 10/1965 Detman ..52/22 purposes without the payment to me of any royalty 3,043,054 7/1962 Schmidt ....52/8l th r on, 2,705,349 4/1955 Shaw ....52/81 1,080,137 12/1913 Carter ..52/199 16 Claims, 18 Drawing Figures PATENTEDAPRS I973 3,724 149 sum 1 BF 5 INVENTOR KENNETH D. DETMAN A ORNEY PATENTEDAPR 3 I975 SHEET 2 OF 5 KENNETH D. DETMAN /%fi4 Wa TTORNEY PATENTEDAPR 3 I975 SHEET 3 OF 5 INVENTOR KENNETH D. DETMAN l m F ATTORNEY Y PATENTEDAPR 3 I973 SHEET u or 5 FIG. I3

INVENTOR ETH o. DETMAN ATTORNEY PATENTEDAPR 3 I975 SHEET 5 BF 5 INVEN'IOR. KENNETH D. DETMAN ATTORNEY VENTILATED, SHADED, WATERPROOF ROOF STRUCTURE BACKGROUND OF THE INVENTION This invention relates to a roof structure made from a number of prefabricated units of suitable material, usually metal. More specifically, it relates to such a roof structure in the shape of a dome, which can be provided with shade, ventilation, both shade and ventilation, or neither, and which can be quickly altered to any of these options without changing the basic roof structure. A conventional roof is not designed to allow it to be easily modified if a change in functions is desired. But if it is desired that a part of a conventional roof be changed to have ventilation alone, shade alone, or both ventilation and shade, the entire portion of the roof to be modified has to be dismantled and rebuilt. Until rebuilding is complete, such dismantling exposes the contents of the building to the elements. With this invention, conversion is accomplished in seconds per unit and involves no exposure.

SUMMARY OF THE INVENTION This invention provides, a dome type roof structure for attachment to a circular concrete foundation, the roof being formed from a plurality of prefabricated, preferably hexagonal pans bolted or fastened together along all edge flanges. Where ventilation or shade options are desired, a type pan is used having a circular nozzled opening in the center and means for covering the opening. Where a smooth surface, airtightness, or security is desired, all pans have an unbroken surface. The outermost ring of bolted or fastened pans are attached to the foundation by means such as bolts in elongated holes to permit expansion, and these pans may be specially shaped to fit the foundation, or preferably, the foundation may be constructed to fit the lower edges of the special pans. The covering means may be means for venting each pan to the atmosphere without exposure, means for shading each pan only, means for venting and shading each pan simultaneously, or means for closing the openings entirely.

Accordingly, it is an object of this invention to provide a prefabricated, dome shaped roof that is easily assembled on the ground.

It is another object to provide a roof of the above character which also has great structural strength.

It is a further object to provide a roof of the above character which can at any time be quickly modified without complete disassembly so as to allow ventilation without shade, shade without ventilation, simultaneous shade and ventilation, or neither shade nor ventilation, of different parts of the roof, all at the same time.

It is still another object to provide a roof of the above character which for special purposes can be made transparent or translucent to light by use of appropriate plastic materials in construction of the basic pan units.

Use of such units in conjunction with metal pan units, to act as windows or skylights is another object of this invention.

It is still another object to provide a roof of the above character which for esthetic and other reasons may be constructed by fastening together only solid top pans to give an unbroken, hemispherical outer surface. A corollary object would be to provide a similar roof with an unbroken, hemispherical inner surface suitable for planetaria, accomplished by simple reversal of flanged edges and bevel to exterior side of solid pans.

Other objects and advantages of the invention will become apparent upon reference to the following drawings and detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a portion of a dome roof utilizing my invention;

FIG. 2 is a portion of a dome roof utilizing my invention with solid pans;

FIG. 3 is an exploded enlargement partially in section of a portion of the roof illustrated in FIG. 1, which depicts an alternate embodiment of my invention;

FIG. 3a and FIG. 3b illustrate other alternate embodiments of my invention with respect to the type of cover which may be utilized;

FIG. 4 is a partial section taken along the line 3-3 of FIG. 3;

FIG. 5 is a partial plan view of the roof illustrated in FIG. 1;

FIG. 6 is a partial plan view of a dome roof illustrating another embodiment of my invention;

FIG. 7 is a partial plan view of a dome roof similar to that .illustrated in 'FIG. 5, but which depicts still another embodiment of my invention;

FIG. 8 is a partial section illustrating the corrugated ring utilized in the embodiment illustrated in FIG. 7;

FIG. 9 is a plan view illustrating the type of special roof unit utilized to attach a door or' window frame to standard roof units and the roof to the foundation;

FIG. 10 is a plan view illustrating a modification of the unit depicted in FIG. 9;

FIG. 11 is a plan view illustrating another type of special roof unit utilized to attach the roof to the foundation or to frames of openings;

FIG. 11a is a sectional view taken on the line 11a- 11aofFIG.l1;

FIG. 12 illustrates a portion of another type of roof dome utilizing my invention, wherein the smooth surface of solid pans is transposed to the inside of the dome and all bolted flanges are on the outside surface;

FIG. 13 is a view partly in section illustrating one possible configuration of special split pan 21 which is used as a temporary center support for raising the dome during assembly and erection;

FIG. 14 is a panoramic view showing assembly of the first ring of pans plus one in a circular type structure; and

FIG. 15 is a perspective view showing the use, in framing doors and windows, of partial pans as illustrated in FIGS. 9, 10 and 11.

DESCRIPTION OF THE PREFERRED EMBODIMENTS This invention may be utilized as a domed roof for cial pan 21 and arranged to move the load upward along a guyed pipe 10. As the roof is assembled in successive rings from the ground, as in FIG. 14, jack 71 is raised as necessary until the full roof diameter and height are obtained. At this point the lower edges of the completed dome are fixed to the foundation (not shown) in a manner hereinafter described. The dome is then self supporting. Center pipe may or may not be retained. If retained, it could be utilized both as a support, a vent, or as a conduit for any conventional purpose.

Turning to FIG. 3 and FIG. 5, in accordance with my invention, the basic unit of the roof comprises a preferably hexagonal pan ll, usually of metal and bolted or fastened along each of its six edge flanges 12 to identical flanges of adjacent pans. To insure watertight construction, a sealant may be used between or along the joined flanges. To provide the variable curvature of the dome, the flanges are formed or machined at an angle slightly removed from the perpendicular to the plane represented by line 14, FIG. 3. Thus, for a pan 12 inches in diameter, having an included flange angle of approximately 89 37", a dome can be constructed having a diameter of 100 feet; or for a pan 18 inches in diameter, having an included flange angle of approximately 88 l8, the dome would have a diameter of 50 feet. The included flange angle is measured between the flange l2 and the center part 16 of the pan. To assist the run-off of water and to promote sphericity, the center part 16 of the pan rises slightly from the plane represented by line 14. To provide for easy modification of the functions of the roof by adding covering units, a circular opening as defined by an upwardly projecting nozzle 18 externally threaded at 20, may be formed in the very center of the pan unit.

Turning to FIG. 13, it shows the special pan 21 which is utilized at the point where the center pipe 10 passes through and supports the roof during erection by bearing on cleated base plate 72 resting on flat ground. This pan is made in two equal halves which are bolted together around pipe 10 to form a pan having the same outside dimensions as standard pans. The center opening has a diameter about one-eighth inch larger than the pipe used, to give an easy sliding fit thereon. The bottom of the pan is flat for seating the load of the dome on the jack 71. Since this pan must carry the entire load it is made of high strength steel.

In accordance with another aspect of my invention, various types of covering units, each having different functions, may be fitted to the nozzle 18, thus allowing the roof to be modified without dismantling the basic pan unit 11. These covers are illustrated in FIG. 3, FIG. 3a and FIG. 3b. Only some of them are used together at any one time on any one pan, as hereinafter described. As will become apparent, any of these covers can be replaced at any time by any of the others. Thus as indicated in FIG. 1, at and 40, some of the pans may have one type of cover while the others may have another.

If no extra function -is.desired for a particular pan other than shelter, a threaded cap 30, as illustrated in FIG. 3a, is screwed into place over nozzle 18. If slight venting of the pan but no shading is required, a threaded cap 32, as illustrated in FIG. 3b, containing bored vent holes 34 is screwed into place over nozzle 18. If shade of the pan is desired, a cover piece 40, having a slightly spherical top plate 41 is slipped into the hollow center of nozzle 18 by means of a hollow center stud 42 depending downwardly from the center of the plate. To support the cover piece on the nozzle, a shoulder 43 is provided on the stud 42 and a perforated flange 44 is provided, extending downward perpendicularly from the plate along its circumference. The flange 44 then rests upon the slightly spherical pan surface 16. Whether or not ventilation is desired with the shade then determinesthe manner in which the center stud 42 is attached to the pan 11. To provide the option of shade without ventilation, the stud 42 is externally threaded at 45 to accommodate a threaded cap 30' similar to but smaller than cap 30 utilized to close the nozzle 18. To allow the stud and cover piece to be removably attached in such a way as to permit ventilation, a spring catch 46 is pivoted to the stud at 48, the spring 50 biasing the catch to engage a groove 52 machined into the nozzle below the threads 20. In this combination, the cap 30' is not used, and air may flow through the stud into or out of the pan. Numerous perforations 56 are provided in the flange 44 to allow air to circulate freely through it. Said perforations are slanted downwardly and outwardly to decrease the possibility of blowing rain penetrating to the space inside the flange. In the event it does, however, the flange 44 is serrated along its lower edge 58 to allow the water to drain off surface 16. To allow the air to circulate from within the flange area into the stud 42, several openings 60 are formed in the upper half ,of the stud and fine screens 62 are inserted therein to keep out insects. If the ventilated and shaded cover is to be secured against removal from the outside, a threaded nut 64 is screwed onto the stud threads 45. To insure that the entire pan is shaded, a flexible ring 66, preferably made of sheet metal is fixed to the plate 41 along the circumference thereof, extending outwardly substantially within the plane of plate 41 to a distance exceeding the diameter of the pan by between a and 2 inches, as will be hereinafter explained in more detail. This excess diameter means that the adjacent rings overlap, as indicated in FIG. 1, but because the rings are annealed sheet metal of a thickness between 0.03 and 0.04 inch, they are sufficiently flexible to allow this. 4

The cover piece ring 66 may be made in two different shapes. As indicated in FIG. 5, the rings may be circular. In that event, to allow circulation of air from under cover piece 40, the ring 66 is about 2 inches wide and has a portion 68 which is corrugated, the troughs extending downward from one inch out in the ring out to the edge (FIGS. 3 and 4). In this embodiment, the corrugation is always placed on the edge closest to the center pan 21 of the dome and is overlapped by the ring of the cover piece 40 positioned more closely to the center. To assist in the placement of each cover piece 40, an arrow 70 is embossed into the plate 41 and points to the midpoint of the corrugated area. Because the roof is a dome, the arrows point upward along spherical radii when seen in plan as in FIG. 5. In the center of the raised fin which is the embossed arrow 70, a 56 inch diameter hole 70' is formed to provide a hold for a wire hook which is used to lift the cover piece from the nozzle.

FIGS. 6, 7 and 8 illustrate alternate embodiments for cover pieces, wherein the shape of the ring 66 is hexagonal rather than circular. The parts in these embodiments which correspond to those previously described have the same reference numerals to which the distinguishing suffixes a and b have been added. Thus, in FIG. 6 the cover pieces 40a have a hexagonal ring 66a and are placed so that each edge except the top edge overlaps the edge of the adjacent ring by one-eighth of an inch. To provide room for the corrugations 68a, the highest edge, again identified by an embossed arrow 70a, extends outward three-eighths of an inch more than the other sides, so that it is overlapped by one-half of an inch. This allows air to circulate through the corrugations as in the circular ring embodiment. Because the hexagon can be rotated between only six positions, this embodiment does not result in all the arrows pointing at the exact center of the dome along spherical radii. However, the covers are placed to the nearest approximation to this as possible.

FIG. 7 illustrates an embodiment similar to that of FIG. 6, except that the cover pieces 40b have the extended corrugated edge 68b on the lowest edge of the ring, and the edge is corrugated upward as illustrated in FIG. 8. Accordingly, in this embodiment the corrugated edge overlaps the upper edge of the adjacent cover piece below it, rather than being overlapped by the adjacent cover piece.

In accordance with still another aspect of my invention, to attach the assembled dome to the foundation or door and window frames, special pans 80, (FIG. 9); 80a, (FIG. 10); and 81, (FIG. 11) are utilized. Such units are necessary in certain places, inasmuch as a ring of hexagons does not present a continuous flat edge or surface such as is normally used for such attachments. These special pans 80, 80a, and 81 are in effect, versions of the pan 11 except that the base is truncated to allow its edge to line up with edges of other units. Bottom flange surfaces 82 of all units resting on foundations have radially slotted holes 84a for larger bolts and to allow for expansion and contraction of the dome. To allow special pans to be bolted to standard pans, matching holes 84 are provided. Because all special pans are truncated, there is neither the need nor the central location, for the nozzle l8,'and therefore these pans lack that opening.

In accordance with still another aspect of my invention, FIG. 2 illustrates a section through a portion of a dome which is constructed of all solid top pans, that is, without nozzles. The top surface 16 of solid top pans may be constructed to the same radius as the completed dome to present a smooth hemispherical surface when viewed from the exterior. This type dome may be used where security is of paramount importance since it is virtually tamperproof. FIG. 12 illustrates a similar dome except that in this case the smooth surface is designed to be on the inside where it could serve ideally as aplanetarium roof. In this type, the flanges and bevels are transposed to the outside and the plan view reveals all bolting of flanges exposed on the exterior. Filling these pans with a cementitious material would serve the double purpose of shedding rainwater and preventing any tampering with the bolts.

FIG. 14 illustrates the initial assembly of the first ring of hexagonal pans to center pan 21 which rests on a collar jack 71, as shown in FIG. 13. Support pole 10, resting on base plate 72, projects vertically through both jack 71 and pan 21, with its upper end secured by guy wires 73. As successive rings of hexagonal pans are attached to the first ring at some convenient working level above ground, the jack is intermittently raised as necessary to keep the lower edge of the growing dome circumference at this same working level. This procedure allows workmen to easily assembly entire dome from the ground. Blocking may be employed from dome to ground at any time to prevent sudden wind damage and promote safety. This process of adding rings and jacking a bit is continued for all remaining rings until assembly of the dome is complete. Blocking is then adjusted to foundation level. The foundation bolts are placed in the lowermost ring flange holes 84a prior to placement of foundation forms and pouring of concrete foundation. Guy wires 73 are removed and pole 10 may be removed if desired. Center pan 21 is removed and replaced by a standard pan as necessary. Foundation may be omitted where dome is for temporary use and later dismantled.

FIG. 15 shows the completed dome using the hexagonal pans l1 and the special pans illustrated by FIGS. 9, l0 and 11 at the foundation and various openings.

A feature of major importance in this invention is interchangeability, wherein any pan designed for a given radius dome, whether solid or nozzle top, is interchangeable with any other pan of like shape in that dome at any time, even after the dome is completed and in use. Removal and insertion of another pan is merely a matter of bolting and unbolting, one at a time, as required Sizes given herein apply to pans about 12 to 15 inches across but there is no theoretical limit to possible sizes. Parts shall generally be in these proportions as to size.

While the invention has been described in connection with preferred embodiments, it will be understood that I do not intend to limit the invention to that described. On the contrary, I intend to cover all alternatives, modifications, and equivalents as may be included within the spirit and scope of the invention as defined by the following claims.

Iclaim:

l. A dome roof structure for attachment to a circular building foundation comprising a. a plurality of joined prefabricated hexagonal pans,

each of said pans having a planar surface with flanges depending therefrom, certain of said pans having aperture means formed in said hexagonal pans and means for selectively sealing and venting said aperture means, said means for selectively sealing and venting said aperture means comprising a vented cover means comprising:

i. a flat plate,

2. a center tube depending downwardly from the center of said plate,

3. means on said center tube for attaching said tube and said plate to said pan at said aperture means formed in said hexagonal pans,

4. a perforated flange extending perpendicularly downwardly from said plate around the perimeter thereof, and v 5. a flexible ring attached to the perimeter of said plate and extending outwardly substantially within the plane of said plate; said pans joined together along said flanges; and

b. means for selectively attaching said joined pans to foundations and structure openings.

2. The roof structure as defined by claim 1 wherein said joined hexagonal pans form a continuous surface.

3. The roof structure as defined by claim 1, wherein said attaching means includes pan units having a trapezoidal configuration wherein the longer base thereof abuts the structure to which it is attached.

4. The roof structure as defined in claim 1 wherein said attaching means includes pan units having an isoceles triangle configuration wherein the longest side thereof abuts the structure to which it is attached.

5. The roof structure as defined in claim 1 wherein said attaching means includes pan units having a configuration defined by a rectangular area joined to a triangular area and wherein an edge of said rectangular area abuts the structure to which it is attached.

6. A roof structure as recited in claim 1 wherein said flat plates and said pans are selectively comprised of light transmitting and opaque material and said covers and said pans are combined to provide light transmitting and opaque portions of said roof.

7. The roof structure as defined in claim 1 wherein:

a. said center tube has openings in its side walls;

b. said flange has a serrated lower edge;

c. said perforations in said flange are slanted downwardly outwardly; and

d. said flexible ring has an arcuate portion of its edge corrugated and the remaining arcuate portion which is flat.

8. The roof structure as defined in claim 7 wherein said corrugations have upwardly directed troughs.

9. The roof structure as defined in claim 7 wherein said corrugations have downwardly directed troughs.

10. A roof structure as defined in claim 7 wherein the corrugated portion of said ring has a flat portion extending outwardly a portion of the distance to the outer edge from the lesser diameter of said ring and the remaining distance to the outer edge comprises a corrugated portion with the depth of the corrugation gradually increasing as the outer edge is approached.

11. A roof structure as recited in claim 7 wherein said corrugated portion of said covers are oriented in a direction toward the apex of the dome of the roof structure.

12. A cover utilized with a roof structure comprising:

a. a flat plate;

b. a center tube depending downwardly from the center of said plate;

c. means on said center tube for attaching said tube and said plate to the roof;

d. a perforated flange extending perpendicularly downwardly from said plate around the perimeter thereof; and

e. a flexible annulus attached to the perimeter of said plate and extending outwardly substantially within the plane of said plate.

13. The cover as defined in claim 12 wherein:

a. said center tube has openings in its sidewalls;

b. said flange has a serrated lower edge;

c. said perforations in said flange are slanted downwardl outwardly; and d. said flexib e annulus as an arcuate portion of its edge corrugated, and the remaining arcuate portion which is flat.

14. A cover as recited in claim 13 wherein the configuration of said annulus is hexagonal.

15. A cover as recited in claim 13 wherein the configuration of said annulus is circular.

16. A structural unit for use in erecting a dome type roof structure comprising:

a. a regular polygonal pan having angled flanges depending therefrom and a central aperture means including a neck portion; and

b. a vented cover means adapted to engage said aperture means, wherein said cover means comprises: 1. a flat plate;

2. a central tube depending downwardly from the center of said plate and adapted to engage said aperture means;

3. means on said central tube for attaching said tube to said pan at said aperture means;

4. a perforated flange extending perpendicularly downward from said plate around the perimeter thereof; and

5. a flexible ring attached to the perimeter of said plate and extending outwardly substantially within the plane of said plate. 

1. A dome roof structure for attachment to a circular building foundation comprising a. a plurality of joined prefabricated hexagonal pans, each of said pans having a planar surface with flanges depending therefrom, certain of said pans having aperture means formed in said hexagonal pans and means for selectively sealing and venting said aperture means, said means for selectively sealing and venting said aperture means comprising a vented cover means comprising:
 1. a flat plate,
 2. a center tube depending downwardly from the center of said plate,
 3. means on said center tube for attaching said tube and said plate to said pan at said aperture means formed in said hexagonal pans,
 4. a perforated flange extending perpendicularly downwardly from said plate around the perimeter thereof, and
 5. a flexible ring attached to the perimeter of said plate and extending outwardly substantially within the plane of said plate; said pans joined together along said flanges; and b. means for selectively attaching said joined pans to foundations and structure openings.
 2. a center tube depending downwardly from the center of said plate,
 2. The roof structure as defined by claim 1 wherein said joined hexagonal pans form a continuous surface.
 2. a central tube depending downwardly from the center of said plate and adapted to engage said aperture means;
 3. means on said central tube for attaching said tube to said pan at said aperture means;
 3. means on said center tube for attaching said tube and said plate to said pan at said aperture means formed in said hexagonal pans,
 3. The roof structure as defined by claim 1, wherein said attaching means includes pan units having a trapezoidal configuration wherein the longer base thereof abuts the structure to which it is attached.
 4. a perforated flange extending perpendicularly downwardly from said plate around the perimeter thereof, and
 4. The roof structure as defined in claim 1 wherein said attaching means includes pan units having an isoceles triangle configuration wherein the longest side thereof abuts the structure to which it is attached.
 4. a perforated flange extending perpendicularly downward from said plate around the perimeter thereof; and
 5. a flexible ring attached to the perimeter of said plate and extending outwardly substantially within the plane of said plate.
 5. The roof structure as defined in claim 1 wherein said attaching means includes pan units having a configuration defined by a rectangular area joined to a triangular area and wherein an edge of said rectangular area abuts the structure to which it is attached.
 5. a flexible ring attached to the perimeter of said plate and extending outwardly substantially within the plane of said plate; said pans joined together along said flanges; and b. means for selectively attaching said joined pans to foundations and structure openings.
 6. A roof structure as recited in claim 1 wherein said flat plates and said pans are selectively comprised of light transmitting and opaque material and said covers and said pans are combined to provide light transmitting and opaque portions of said roof.
 7. The roof structure as defined in claim 1 wherein: a. said center tube has openings in its side walls; b. said flange has a serrated lower edge; c. said perforations in said flange are slanted downwardly outwardly; and d. said flexible ring has an arcuate portion of its edge corrugated and the remaining arcuate portion which is flat.
 8. The roof structure as defined in claim 7 wherein said corrugations have upwardly directed troughs.
 9. The roof structure as defined in claim 7 wherein said corrugations have downwardly directed troughs.
 10. A roof structure as defined in claim 7 wherein the corrugated portion of said ring has a flat portion extending outwardly a portion of the distance to the outer edge from the lesser diameter of said ring and the remaining distance to the outer edge comprises a corrugated portion with the depth of the corrugation gradually increasing as the outer edge is approached.
 11. A roof structure as recited in claim 7 wherein said corrugated portion of said covers are oriented in a direction toward the apex of the dome of the roof structure.
 12. A cover utilized with a roof structure comprising: a. a flat plate; b. a center tube depending downwardly from the center of said plate; c. means on said center tube for attaching said tube and said plate to the roof; d. A perforated flange extending perpendicularly downwardly from said plate around the perimeter thereof; and e. a flexible annulus attached to the perimeter of said plate and extending outwardly substantially within the plane of said plate.
 13. The cover as defined in claim 12 wherein: a. said center tube has openings in its sidewalls; b. said flange has a serrated lower edge; c. said perforations in said flange are slanted downwardly outwardly; and d. said flexible annulus has an arcuate portion of its edge corrugated, and the remaining arcuate portion which is flat.
 14. A cover as recited in claim 13 wherein the configuration of said annulus is hexagonal.
 15. A cover as recited in claim 13 wherein the configuration of said annulus is circular.
 16. A structural unit for use in erecting a dome type roof structure comprising: a. a regular polygonal pan having angled flanges depending therefrom and a central aperture means including a neck portion; and b. a vented cover means adapted to engage said aperture means, wherein said cover means comprises: 